RenalGuard system in high-risk patients for contrast-induced acute kidney injury.

BACKGROUND: High urine flow rate (UFR) has been suggested as a target for effective prevention of contrast-induced acute kidney injury (CI-AKI). The RenalGuard therapy (saline infusion plus furosemide controlled by the RenalGuard system) facilitates the achievement of this target. METHODS: Four hundred consecutive patients with an estimated glomerular filtration rate ≤30 mL/min per 1.73 m(2) and/or a high predicted risk (according to the Mehran score ≥11 and/or the Gurm score >7%) treated by the RenalGuard therapy were analyzed. The primary end points were (1) the relationship between CI-AKI and UFR during preprocedural, intraprocedural, and postprocedural phases of the RenalGuard therapy and (2) the rate of acute pulmonary edema and impairment in electrolytes balance. RESULTS: Urine flow rate was significantly lower in the patients with CI-AKI in the preprocedural phase (208 ± 117 vs 283 ± 160 mL/h, P < .001) and in the intraprocedural phase (389 ± 198 vs 483 ± 225 mL/h, P = .009). The best threshold for CI-AKI prevention was a mean intraprocedural phase UFR ≥450 mL/h (area under curve 0.62, P = .009, sensitivity 80%, specificity 46%). Performance of percutaneous coronary intervention (hazard ratio [HR] 4.13, 95% CI 1.81-9.10, P < .001), the intraprocedural phase UFR <450 mL/h (HR 2.27, 95% CI 1.05-2.01, P = .012), and total furosemide dose >0.32 mg/kg (HR 5.03, 95% CI 2.33-10.87, P < .001) were independent predictors of CI-AKI. Pulmonary edema occurred in 4 patients (1%). Potassium replacement was required in 16 patients (4%). No patients developed severe hypomagnesemia, hyponatremia, or hypernatremia. CONCLUSIONS: RenalGuard therapy is safe and effective in reaching high UFR. Mean intraprocedural UFR ≥450 mL/h should be the target for optimal CI-AKI prevention.